The problem stems from the fact that the engines are less likely to trust new microsites because they typically suffer from a lack of inbound links and have a young domain age. "It stands to reason that the older a domain is the more legitimate it probably is," Dr. Naveel says. "When you build a microsite on its own domain or even a subdomain, you're essentially starting from scratch. There is no history for the search engines to rely upon. So, all of your separate microsite domains are fighting on their own when they could be piggybacking on the trust your main website domain has already established simply by creating a section for them."